Very Low Profile Fully Buffered DIMM Bill Gervasi Vice President, DRAM Technology SimpleTech The subject matter of this presentation is a work in progress. It had not been balloted or approved as a final JEDEC standard. Users should not rely on this presentation as indicative of the content of the final standard. JEDEC does not endorse the content of this presentation. The views expressed are solely those of the author(s).

The subject matter is a work in progress, not a final JEDEC standard. Fully Buffered DIMM Designed for needs of mid-range servers –Typically 8 or 16 FB-DIMM slots –4GB per slot by the time it is ramping (1Gb DRAMs)  32GB & 64GB servers –Only “standard” height is 30mm (1.2”) Need to penetrate broader markets to ensure success and reduce cost

The subject matter is a work in progress, not a final JEDEC standard. Form Factor Wars 1.2” (30mm) standard chosen in 1999 based on 1U server market projections But, market fragmenting –Blade needs 18.3mm (VLP) –1U needs 30mm (LP) –2U can use 38mm or taller OEMs “demand” one size fits all … but …

The subject matter is a work in progress, not a final JEDEC standard. High Profile Module 2U Server Side View Lots of headroom due to huge heat sinks Tall module (e.g., 38mm) fits fine Better thermal characteristics More DRAM supplier options 30mm 38mm CPU Heat Sink

The subject matter is a work in progress, not a final JEDEC standard. Standard Profile Module Angled Socket mm 2 Cool AirHeated Air Top View CPU 30 mm DIMM Blade Server

The subject matter is a work in progress, not a final JEDEC standard. Very Low Profile Module Angled Socket Vertical Socket 2 x 2200 mm 2 75% Reduction! Cool AirHeated Air Blade Server 30 mm DIMM 18.3 mm DIMM CPU Top View

The subject matter is a work in progress, not a final JEDEC standard. The VLP Form Factor mm (5.25”) 4 mm (0.158”) 14.3 mm (0.56”) Usable Layout Area 18.3 mm (0.72”)

The subject matter is a work in progress, not a final JEDEC standard. FB-DIMM Differentiation How to build a better FB-DIMM –Improved thermal solutions –How about a VLP FB-DIMM? Challenge #1: AMB is 19.2mm tall! Good thing guys like us like to pack 10 pounds into a 5 pound sack… 19.2 mm (0.76”) 24 mm (0.95”)

The subject matter is a work in progress, not a final JEDEC standard. FB-DIMM Differentiation Notice that the AMB has huge windows in the array This choice was based on some assumptions: –FB-DIMM must be possible in 6 layers –No blind vias required However, what if you’re willing to go to 8 layers and use blind vias?

The subject matter is a work in progress, not a final JEDEC standard. Honey, I Shrunk the AMB 655 ball AMB 29x23 ball array (ball pitch 0.8mm) 24.5 x 19.5mm package 510 ball VLP-AMB 31x17 ball array (ball pitch 0.8mm) 26 x 14mm package

The subject matter is a work in progress, not a final JEDEC standard. Can the AMB Be THAT Small? The AMB die size is not the limiter… it’s the number of balls on the package that defines its footprint.

The subject matter is a work in progress, not a final JEDEC standard. VLP FB-DIMM Stacked 2GB

The subject matter is a work in progress, not a final JEDEC standard. DRAM Size Max DRAM package supported in VLP = 12.3 x 14.3 mm This supports most 512Mb chips now 1Gb shrinks with 70 nm process –4GB VLP FB-DIMM enabled

The subject matter is a work in progress, not a final JEDEC standard. A Simpler Variation Primary-only interface – no southbound Uses 4-channel memory controller Eliminates 100 balls, 1W per AMB “Low End” FB-DIMM Controller “High End” FB-DIMM Controller

The subject matter is a work in progress, not a final JEDEC standard. Current Status Getting customer input on primary-only AMB Mechanical feasibility done Re-ballout analysis under way with AMB suppliers Thermal analysis under way –Improved airflow with lower ambient –Less radiating space –Heat sinking solutions to be developed Socket analysis begun

The subject matter is a work in progress, not a final JEDEC standard. Thank You Questions? Bill Gervasi